Comparison of Estimated Conductor Costs between a Superconducting Thin-film Fault-current Limiter (FCL) and a Coated-conductor-based Superconducting FCL

We recently proposed a new design for a high-temperature superconducting thin-film fault-current limiter (FCL), which uses high-resistivity Au-Ag alloy shunt layers instead of the pure gold (or silver) shunt layers conventionally used. Due to the much larger resistance of the Au-Ag alloy layers, the FCL elements withstood very high electric fields (> 40 Vpeak/cm), and realized a very high switching power density, ∼2.0 kVA/cm2. The composition of our FCL element is very simple, and the achieved power density is more than five times higher than conventional devices, which leads to a dramatic reduction in the amount of expensive superconducting thin films required. Similarly, Kinder et al. recently proposed a new coated-conductor-based FCL element, which achieved a relatively high electric field of 2.7 Vpeak/cm. We estimated the cost of our thin-film FCL elements used in a typical 6.6 kV FCL that is introduced in a distributed power supply site. We also estimated the cost of coated conductors used to produce the FCL, and compared the two.